Bearing manufacturers customarily enclose and seal the moving balls or rollers and cages between the outer and inner races of rolling bearings, using flat ring-shaped or washer-shaped seals or shields to enclose the moving parts. The outer rims of these seals or shields are customarily flanged axially outward, and the flange is spread radially in a crimping operation into a concave groove formed in the outer portal rim of the outer race on both sides of the rolling members.
The inner rim of the seal or shield closely adjoins the inner race, and for heavy duty applications with farm machinery, utility vehicles and military equipment which may encounter dirt, dust and sand, the inner rim of the seal may be formed of one or more rings of rubber sheet or molded rubber material bearing against the inner race and designed to keep lubricants inside the bearing assembly, and dirt outside.
During bearing manufacture, heat treatment exposes the outer bearing race to high temperatures which often distort the roundness of the bearing race from its original machining, and the nominal dimensions can be subject to wide tolerances, as much as 0.005 to 0.015 inches. Following heat treatment, the groove to receive the rolling members in the outer cylindrical rim, as well as the end wall rims of the outer race are all ground to exact tolerances, and are perfectly round, to be seated in bearing seats or sleeves and to receive the rolling members in exact circular orbit.
Heat treatment distortion of the outer bearing race may however leave the convex seal groove in the portal end of the outer bearing race distorted and out of round. As a result, when the flanged ring seals are placed in position and their outer rim flanges are spread radially outwardly during the crimping operation, they may engage the outer race only at two smallest-diameter points. The ring seals may provide very poor contact or lack of engagement at other points where the effective diameter of the distorted convex seal groove is larger. The outer bearing race is often thrown out of round beyond allowable tolerances by seal-crimping stress applied at only two points by the crimped ring seal. In addition, the ring seal may not reach the groove except at these two points, and this permits lubricant to escape and dirt, dust or foreign objects to enter the bearing, making the seal inadequate.
The crimp tooling of the present invention solves these problems by applying independent crimping forces at a plurality of points around the periphery of the ring seal. These independent crimp forces are substantially equal by reason of the symmetrical geometry of the crimp tooling, and dimensional variations in the seal groove receiving the crimped seal merely allow different portions of the seal rim to be crimped independently to match any such dimensional variations. Crimping deformation is thus uniformly distributed about the periphery of the ring seal and stress concentrations at only a few minimum diameter points are substantially eliminated, making the sealing operation more uniformly effective and avoiding any crimping distortion of the bearing assembly itself.
In the crimp tooling of the present invention, the independent crimping forces are applied by a plurality of sector rams peripherally arrayed around the rim of sealing rings presented at the work station for crimping. Each sector ram is actuated by independent crimping force supplied by an independent hydraulic piston-cylinder unit, whose force may be transmitted to the sector ram by a radial lever in the tooling assemblies of the preferred forms of the invention.
Accordingly, a principal object of the present invention is to provide crimping tooling for seal rings for rolling bearings which minimizers or eliminates distortion of the outer races resulting from the crimping operation.
A further object of the invention is to provide such crimping tooling methods and devices which produce highly efficient crimping installation of ring seals in rolling bearing races while significantly improving the sealing operation thereof.
Still another object of the present invention is to provide such ring seal crimping methods and apparatus which are well adapted for incorporation in automatic production line equipment for rolling bearing manufacture.
A further object of the invention is to provide rolling bearing seal crimping methods and devices which are adapted for incorporation in production line equipment in which both ends of each rolling bearing are successively sealed and crimped as they progress along the automatic or semi-automatic production line.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others thereof, and the features of construction, combinations of elements, and arrangements of parts which will be exemplified as hereinafter set forth, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings, in which: